FIELD OF THE INVENTION
The invention relates to an electrical conductor having a longitudinal direction and a stacking direction perpendicular to the longitudinal direction, which can be stacked with a plurality of identical conductors with the interposition of an insulating layer between each two adjacent conductors, the conductor having two substantially flat main sides oriented perpendicular to the stacking direction and having at least a set or multiplicity of slots being disposed in succession approximately in the longitudinal direction, each leading approximately in the stacking direction through the conductor and having a mouth in each main side.
Such electrical conductors find many uses in windings of electrical machines, particularly in the windings of turbo generators that are cooled with a coolant gas, in particular air or hydrogen, in order to dissipate the heat produced during operation. Electrical conductors of that type, like their use in the windings of electric machines, are described in a book entitled "Herstellung der Wicklungen Elektrischer Maschinen" [Manufacture of the Windings of Electrical Machines], edited by H. Sequenz, Springer Verlag, Vienna and New York 1973, particularly in an article by D. Lambrecht contained in that book and entitled "Lauferwicklungen fur Turbogeneratoren" [Rotor Windings for Turbogenerators] (page 169 ff.). In order to select the material for an electrical conductor of the type described, reference may be made in particular to an article that is also contained in that book, entitled "Leiterwerkstoffe" [Conductor Materials] by R. Knobloch (page 1 ff.). An example of the use of an electrical conductor of that kind may be found in European Patent No. 0 160 887 B1.
As described in detail particularly in the article by D. Lambrecht, electrical conductors of the type described are typically stacked one above the other in a stacking direction perpendicular to the longitudinal directions of the electrical conductors in order to form a winding for an electrical machine, optionally using intermediate insulating layers. Slots in electric conductors and insulating layers that are adjacent to one another are made to overlap at least partially with one another, so that they communicate among one another to form cooling conduits leading through the stacked electrical conductors. The cooling conduits are oriented substantially parallel to a plane defined by the mutually parallel longitudinal directions and by the stacking direction. During operation of the winding, the cooling conduits are flooded with coolant gas, in particular air or hydrogen, as is explained in detail in the references cited.
German Published, Prosecuted Application DE-AS 1 242 744 and German Patent DE-PS 1 242 744 describe an electrical conductor with a longitudinal direction and a stacking direction perpendicular to the longitudinal direction, which can be stacked with a plurality of identical conductors in the stacking direction, and in which at least one insulating layer is to be inserted between each two conductors. The conductor is defined by two substantially flat main sides being oriented perpendicular to the stacking direction and having a set of slots, which are disposed in succession approximately in the longitudinal direction and each of which leads in the stacking direction through the conductor and has a sharp-edged mouth in each main side. At boundary edges, each slot has groove-like milled cuts, which are filled by bush-like adapter pieces of insulating material when this conductor is stacked together with other conductors.
U.S. Pat. No. 4,152,610 discloses a stackable electrical conductor with a set of slots that lead in a stacking direction through the conductor which has a longitudinal groove, oriented parallel to a longitudinal direction of the conductor, for forming a coolant conduit.
German Published, Non-Prosecuted Application DE-OS 1 438 335 describes a stack of electrical conductors being insulated from one another by insulating layers with slots oriented in the stacking direction, in which a slot of a conductor communicates with a slot of an adjacent conductor through a conduit oriented at an angle to a common longitudinal direction of the conductors. Such a conduit may be made in the insulation and/or in one of the conductors.
When the slots are produced in the electrical conductors, special care and therefore in accordance with current practice expensive post-machining of the stamped or milled slots is necessary, as is explained in detail in the article by D. Lambrecht cited above, among other sources, in order to avoid undesired electrical connections in the form of short circuits and the like between two electrical conductors resting on one another and between which there is only a thin insulating layer. Therefore, conventionally the mouths of the slots must be deburred and rounded off or beveled by subsequent countersinking, embossing or the like, which despite the attendant effort and especially the attendant expense is considered too important to be omitted.